Sanding and polishing attachment for electric handsaw supporting and driving units



E. J. STRANDBERG March 13, 1951 I 2,544,810

- SANDING AND POLISHING ATTACHMENT FOR ELECTRIC'HAND SAW SUPPORTING AND DRIVING UNITS Filed April 30, I948 2 Sheets-Sheet 1 March 13, 1951 E J STRANDBERG 2544,810

SANDING AND POLI SHING ATTACHMENT FOR ELECTRIC HAND SAW SUPPORTING AND DRIVING UNITS Filed April 30, 1948 2 Sheets- -Sheet 2 Jig INVENTOR. Edna J 5 2 /27/70 y BY v Patented Mar. 13, 1951 SANDING AND POLISHING ATTACHMENT FOR ELECTRIC HANDSAW SUPPORTING AND DRIVING UNITS Edwin J. Strandberg, Deadwocd S. Dak.

Application April 30, 1948; Serial N'0.- 24,306

1 Claim.

This invention relates to an attachment adapted for use with conventional electric hand saw supporting and driving units for sanding or polishin'g surfaces and more particularly relates to an attachment of extremely simple construction to which an electric hand saw support and drive can be readily applied after removal of the saw blade and guard for utilizing the motor and driven shaft of the hand saw drive as the driving means for the attachment.

Another object of the invention is to provide an attachment of the afor'edescribed character wherein the handle of the hand saw support can be utilized for grasping and operating the attachment.

Still a further object of the invention is to provide a sanding or polishing attachment which is so constructed that endless sanding or polishing elements may be quickly applied to or removed from the attachment.

Still a further object of the invention is to provide an attachment having an extremely simple yieldable mounting for maintaining at all times a proper tension of the endless surface engaging element and to facilitate applying and removing the element.

Various other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawings, illustrating a presently preferred embodiment thereof, and wherein:

Figure 1 is a side elevational view showing the attachment with a conventional power hand saw supporting and driving unit shown demountably applied thereto;

Figure 2 is a longitudinal, horizontal sectional View, taken substantially along a plane as indicated by the line 2-2 of Figure 1; I

Figures 3 and 4 are cross sectional views taken substantially along plane as indicated by the lines 33 and 4- 1, respectively, of Figure 1;

Figure 5 is a longitudinal sectional View taken substantially'ralong a plane as indicated by the line 5-5 of Figure 4, and

Figure 6 is across sectional view taken substantially along a plane as indicated by the line 66 of Figure 1. 1

Referring more specifically to the drawings, the sanding and polishing attachment in its entirety is designated generally 1 and includes a housing, designated generally 8 having a top wall 9 provided with downwardly and inwardly curved end portions forming the ends I!) and I l for the housing 8, and a depending side wall I2 which extends from end-to-end of the housing 8 and from (Cl. Sit-176) 2 the top wall 9 downwardly to the level of the bottom edges of the end walls In and II, as clearly illustrated in Figure 1. The opposite side of the housing 8 is open as clearly illustrated in Figure '1, for a purpose which will hereinafter become apparent.

Referring particularly to Figures 2 and 3, an upright spacing bar I3 is welded or otherwise secured as seen at I4 in an upright position to the inner side of the side wall l2 adjacent the end wall I l and has two longitudinally extending rods I5 welded or otherwise secured to the inner side thereof and with said rods disposed one above the other, as clearly illustrated in Figures 1 and 3. The rear ends of the rods l5, which are located adjacent the spacer bar l3 are connected by an upright bar I6. An elongated bushing I1 is provided with an elongated and enlarged head I8 at one end thereof which is secured by additional welds It to the opposite side of the rods I5 in opposed relationship to the spacing bar I3.

A pulley I9 is provided with a recess extending approximately a half its length as seen at 20 and which opens outwardly at one end thereof to accommodate the bushing l I, said pulley l9 having a longitudinal bore 2| communicating with said recess and opening outwardly of its opposite end, which is slightly recessed as seen at 22 to receive the restricted end 23 of a shaft 24 which is journaled in the bushing I1 and which extends through aligned openings of the side wall I2, bar I3 and element I8, in which openings said shaft is rotatably disposed. The terminal of the restricted end 23 of the shaft 24 is threaded to engage a nut 25 which bears against the recessed end 22 of the pulley I9 for detachably fixing the pulley to the shaft 24 for rotation therewith.

A pair of corresponding upright spacer bars 26 are secured in longitudinally spaced relationship to the inner side of the side wall I2 by additional weld I4, by means of which the intermediate portions of the rods I5 are secured to said spacer bars 26 and, accordingly to the side wall [2. A shoe 2'! is provided with an upstanding flange 28 at one side edge thereof which is secured to the inner sides of the intermediate portions of the rods l5 by additional welds M, as seen in Figure 2 for supporting said shoe 2! in a fixed position relatively to the housing 8 beneath and substantially parallel to the open bottom thereof, as seen in Figure 1. The shoe 2! is provided with upwardly curved ends 29, for a purpose which will hereinafter become apparent.

against the forward end of the rod l5 which is reciprocally disposed in said tube so that the tubes and head 3| are urged forwardly of the housing 8 and away from the rods l5. A bushing or bearing 33 is secured in an upright position to corresponding portions of the inner sides of the tubes 30 by additional welds l4 and said bearing or bushin 33 projects transversely from the inner sides of the tubes 30 and provides a journal for the enlarged end 34 of a shaft which has an elongated restricted end 35 which projects from said enlarged end toward the open side of the housing 8. The shaft 34, 35 constitutes an idler shaft and mounts a pulley 36 having a recessed end 3'! for accommodating the bushing or hearing 33 and the enlarged end 34 of the shaft. The pulley 36 has a central bore 38 extending longitudinally therethrough through which extends the restricted shaft portion 35 which has a threaded terminal for receiving a nut 39 which seats in the opposite recessed end 40 of the pulley 36 and which is tightened for clamping the idler pulley 36 to the shaft 34, 35. It will thus be seen that the idler pulley and shaft are mounted by the tubes 30 on the rods |5 for reciprocatin movement longitudinally in the housing 8 and are normally urged by the springs 32 toward the forward end ll) of said housing.

As clearly illustrated in Figure l, the pulleys l9 and 36 are of approximately the same diameters and depend substantially the same distances below the open bottom of the housing 8 and to substantially the same level as the shoe 21. It will be readily obvious that by applying a manual pressure to the idler pulley 36 that said i pulley together with the tubes 30 can be forced toward the rear end of the housing 8 and away from its front end wall If! by compressing the spring 32 so that an endless surface engaging element 4| such as an endless sanding or polishing strip, may be readily applied over the pulleys l9 and 36 after which, upon release of the pulley 36, the springs 32 will project said pulley and the tubes 30 forwardly or toward the end wall H) for tensioning the strip 4| on the pulleys l9 and 36 so that said strip will be revolved in the housing 8 when the pulley i9 is driven, as will hereinafter be described.

A V-belt pulley 42 is fixed to the end of the shaft 24 which is disposed externally of the side wall |2 and has an endless V-belt 43 trained thereover and which is also trained over a similar belt pulley 44 which is fixed to one end of a driven shaft 45. The driven shaft 45 constitutes a part of a conventional electric hand saw supporting and driving unit 46 from which the circular saw blade and saw guard have been removed and the open bottom of the housing 41 of which is disposed on the upper side of the top wall 9 of the housing 8 and detachably secured thereto by fastenings 48 which rise from the top wall 9 and extend through apertures, not shown, in end flanges 49 of the housing 41. If desired, the fastenings 48 could be adjustable longitudinally of the housing 8 for adjustably positioning the unit 46 thereon to vary the tension of the belt 43. The handle 50 of the saw housing 41 will provide the handle for the attachment I when in use and the shaft 45 is driven by the electric motor, not shown, of the unit 46 in a clockwise direction for driving the belt 43 and pulleys 42 and 44 as well as the pulleys l9 and 36 and the endless element 4| in the same direction so as to cause the attachment to normally move in the direction as indicated by the arrow 5| in Figure 1 when the bottom flight of the element 4| is in contact with a surface to be sanded or polished. The unit 46 i provided with a conventional electric cord 52 adapted to be connected to a suitable source of electric current for operating the electric motor thereof. As seen in Figure 1, the shoe 2'1 extends between the pulleys l9 and 36 and has its upturned ends 29 located adjacent said pulleys for holding the bottom flight of the endless element 4| in substantially a horizontal plane so that all portions thereof will contact the surface to be sanded or polished.

Various modifications and changes are contemplated and may obviously be resorted to, without departing from the spirit or scope of the invention as hereinafter defined by the appended claim.

I claim as my invention:

A surface treating attachment for a portable power unit comprising, a housing adapted to be detachably connected to a portable power unit and supported therebeneath, said housing including a top wall, a side wall and end walls and having an open side and an open bottom, a shaft 1 journaled in the side wall, drive means adapted to connect the shaft to the power unit for revolving the shaft from the power unit, a pulley fixed to the shaft and disposed to revolve in the housing, a pair of rods disposed within and longitudinally of the housing and secured to said side Wall, said rods having portions disposed remote to said shaft and spaced from the side wall, .a carriage mounted for sliding movement longitudinally in the housing including tubes slidably engaging said rod portions and having closed ends disposed beyond the terminals of said rod portions, expansion springs disposed in the tubes between their closed ends and said terminals of the rod portions for urging the carriage away from the shaft, 2. second shaft fixed to and projecting laterally from the carriage, a second pulley journaled on the second shaft, and an endless surface engaging element trained over said pulleys and having a bottom flight located beneath the open bottom of the housing to engage a surface to be treated, said rods and carriage being disposed in a plane parallel to the side wall and between the side wall and the ends of the pulleys disposed adjacent thereto.

EDWIN J. STRANDBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

